The invention relates generally to methods of data transfer and specifically to the transfer of data packets over a broadcast radio frequency channel coordinated with a separate point-to-point digital data transfer system, such as a telephone modem-linked Internet access.
The xe2x80x9cInternetxe2x80x9d (also referred to as the World Wide Web) is a global network of interconnected data links by which various types of data service or functionalities are available to individuals accessing the network via a computer. Both the data service locations and the individuals have unique network addresses on the Internet. Data service or access to the Internet is provided by Internet Service Providers (ISP""s) to residential and commercial subscribers. Each subscriber gains access to the Internet in the form of a separate operative session. Such sessions operate simultaneously and independently of each other. Each subscriber at a respective address can initiate a session through the use of a computer connected to an ISP at its respective address on the Internet. The ISP provides a competitively priced package of functionalities tailored to one or more types of subscribers, including at least basic access to the Internet. Additional services that are frequently made available include electronic mail, access to one or more Internet search engines, known as browsers, chat rooms, news features, weather information, and advertising space. Such functional features appear on the subscriber""s computer screen as choices and, when selected, connect to the source providing that feature, so that the selected functional feature appears on the subscriber""s screen. Because there is a basic access to all Internet addresses, the subscriber can contact and interact with any Internet address to obtain information or a file from that address, more commonly known as xe2x80x9cdownloading the filexe2x80x9d from that address. A typical subscriber session is an electronic communication with the ISP requesting a selected functionality, and also through the ISP to various other network locations on the Internet which provide selected additional functionalities or files which can be downloaded to the subscriber""s computer.
Typically, most electronic data traffic in a given subscriber session consists of a dialog of inquiries and responses paced at the timing of human discourse. While graphics data accompanies much of this traffic, the relative size of each portion of the dialog compared to the movement of substantially large files of data is small. On occasion, the subscriber may request receipt of a large file containing any of numerous data-types, e.g., it can have a particular digital format and a narrowly tailored application. A large file can be an exceptionally large text file, or it can be a file representing a scanned photograph, a video recording in the form of a sequence of video frames, or a file containing computer-executable code such as a software application, computer game, or operating system component. Thus, it can be appreciated that data transfers requested by typical subscribers on the Internet are bursty, i.e., small or large amounts of data are requested, followed by little or no data requests for periods of time.
One major problem with downloading large files from the Internet is the capacity of the network to convey large files at speeds acceptable to the Internet subscriber. Capacity is defined by the available bandwidth of the particular network route over which the files are transmitted, and low available bandwidth results in longer download times. An additional consideration is the manner in which both the subscriber""s computer and the source of the transmitted file are connected to the Internet. While each network link comprising the particular route the file travels between source and subscriber destination has an associated bandwidth, both the initial and the final link between the ISP and the subscriber can be the most troublesome. When a modem connection to a public-switched telephone line is employed, communication though the data network is constrained to data rates in the tens of kilobits per second (e.g., 11, 16 or 56 kbits per second) or low hundreds of kilobits per second in the case of a hard-wire equivalent integrated services digital network (ISDN) line. As an alternative, cable television providers offer a high speed connection service through a cable modem. However, use of a cable modem is expensive because the cable connection is priced at premium levels. A cable modem connection is a full-time connection, not an on-demand connection, as opposed to a modem connected to a telephone line.
Various methods have been proposed to shorten the time required to download large data files by utilizing more than one data path. For example, U.S. Pat. No. 5,181,107 to Rhodes, discloses an information service distribution system wherein a terminal device connected to a television network and to a point-to-point, public-switched telephone line. A subscriber requests a menu of information services (or already has a menu from a previous request) over the telephone line. After appropriate identification has been made for billing purposes, the subscriber can request a selection from the menu (or pay for additional use of a previous selection), such as a video game, dating services, shopping selection, etc., stored in a remotely located information services storage center. In response to the request conveyed over the telephone link, the center transmits files encoded as digital bit streams over a television broadcast channel. While menus are received and decoded by all subscribers, only the requested file is decoded at the requesting subscriber location. There are several drawbacks to this system. For example, the system is restricted to selections from a fixed menu; selected information service is displayed/interacted with only on the subscriber""s television set; there is no access to all downloadable files available on the Internet; and there is no choice between point-to-point and broadcast downloading paths.
U.S. Pat. No. 5,768,539 to Metz et al., discloses a downloading generating system that utilizes a broadband digital broadcast channel and a separate narrow band two-way data communications channel. The digital broadcast network includes provision for downloading executable applications software over one broadcast channel and video programming over a second broadcast channel. The two channels can be multiplexed on a single transport stream. The narrow band two-way data communications capability is for signaling interactive text services such as video file requests. The system includes a set-top device at the subscriber location which, when instructed by the subscriber, transmits data request signals over a narrow band two-way data channel provided by a public switched telephone network or alternatively, by a coaxial cable, e.g., a cable television network cable. The data requests are relatively short messaging-type communications which can be accommodated on the available narrow band two-way data channel. The data provider, which can be an ISP, responds by downloading both packets of executable code and the requested video data file in the form of compressed data for a plurality of video frames to the subscriber over the digital broadband channels. The downloaded executable code, along with a resident software application, are stored and executed in a protected memory device that includes an operating system in the subscriber""s set-top terminal. The set-top terminal can emulate a CATV tuner/decoder for channel selections. Execution of the downloaded code received over the first broadcast channel in turn controls selective capture and presentation of audio and video segments received over the second digital broadcast channel. The billing and other administrative data is communicated to the subscriber over the narrow band two-way data channel.
The Metz et al. system is principally directed toward video-on-demand wherein a known library of video programming is maintained for on-demand download requests by subscribers. While this arrangement enables the transport of digital program information over a relatively fast digital broadcast channel, it is limited to first downloading executable control code into the memory of a subscriber""s set-top terminal, and then utilizing that executable control code to control the operation of the set-top terminal to identify and receive a specific data-type, i.e., the audio and video segments of the program information, as distinguished form any executable computer control code. A disadvantage of the system disclosed in the Metz et al. Patent is that it does not offer the capability of downloading generally any file obtainable from any source on the Internet to a specified subscriber on a demand basis. In addition, executable code must be downloaded over the broadband network to the subscriber to enable the subscribers computer to identify and download the accompanying digital program information.
Internet subscribers generally require, on an on-demand basis, the download of one or more large data files of a wide variety of data-types, where the data file could be obtained from any source connected to the Internet. A common complaint by Internet subscribers is that the data transfer rate over telephone lines, a procedure now commonly in use, is slow. Further, complicating the picture, as computers make increasing use of graphics and audio/video segments, the size of downloaded data files will continue to grow. However, the faster ISDN lines needed to handle large files are expensive to install and maintain.
Downloading operating systems such as the above-described system of Metz et al., do not provide general access to available files on the Internet in combination with a choice of download resources, i.e., over slower (and cheaper) telephone lines, or over faster (and more expensive) broadcast channels. A low cost system is needed that significantly reduces download response time Internet subscribers while enabling such users to use the narrow band communications resources provided by a public-switched, point-to-point telephone lines for communicating request-response type Internet communications between the subscriber and the subscriber""s ISP. A further need is for such a low cost system that provides an option of sharing the use of a high data rate broadcast data channel for downloading substantially large amount of data, regardless of its data-type and source on the lntemet.
In accordance with this invention, a system for enhancing the process of downloading files from the Internet, includes a low cost data receiver for receiving radio frequency signals, a digital data demodulator and software components located both at an ISP and at the subscriber""s location, that together enable an Internet subscriber to select and communicate a choice of available high speed and low speed download paths for downloading a data file from a downloading source to the subscribers computer. The high speed download path option may comprise one or more broadcast data channels, such as, or example, a digital television broadband broadcast channel. The relatively slower low speed download path option may comprise a narrow band, two-way, point-to-point data channel, such as, for example, a public-switched telephone line.
The broadcast data channel transmits alternatively any one or more types of a stream of digital data packets forming part of a broadcast signal. The point-to-point data transfer channel may be a telephone modem link, such as a public-switched telephone modem link, connected between a subscriber-located computer and an ISP. The data receiver is any data receiving means, e.g., a radio frequency receiving means such as a high definition digital television (HDTV) tuner, analog television tuner, radio tuner or satellite receiver. The demodulator is a system for demodulating digital data from the data receiver and transferring the demodulated data to software residing in the subscriber-located computer.
To accomplish this arrangement, a high speed link is provided between an Internet service provider (ISP) and one or more broadcast data channel providers, and a separate well known lower speed link is provided between the ISP and the subscriber. A third link receivable by all subscribers (and non-subscribers who lack the appropriate data receiver and therefore cannot detect the presence of the downloaded file contained within the broadcast signal), is a broadcast channel originating from the broadcast channel provider.
The option of sharing the use of a high data rate broadcast data channel provided by a broadcast channel provider, for downloading substantially large amounts of data, regardless of its data-type and source on the Internet, depends in part on the availability of the unused portion of the broadcast data channel, i.e., the unused bandwidth. Content providers, such as the NATIONAL BROADCAST CORPORATION(trademark), Inc., which own and operate numerous television broadcast stations in major metropolitan areas, are implementing a capability for broadcasting digital television signals over a television channel allocated to them by the Federal Communications Commission (FCC). The television channels are connected to the television subscriber by numerous well known methods, for example by television transmission or by cable television network providers. The FCC permits the use of the 19.3 Mbit/second data rate digital signal to include both audio and video information with unused bandwidth to be made available for other purposes. According to the present invention, one such purpose is to provide the extra data bandwidth to the ISP, thereby providing an additional revenue stream to the broadcaster from the otherwise unused portion of the data bandwidth. The above-described large data files downloaded from an ISP to one of many Internet subscribers, who receive Internet connectivity services from that ISP, advantageously can be communicated over the bandwidth available on the digital broadcast channel.
When a subscriber in networked communication with an ISP that provides Internet connection service to the subscriber over a narrow band two-way data channel transmits a request to download a large data file (which may originate from any addressable location on the Internet), software located at the ISP queries an updated broadcast channel availability status file to determine unused bandwidth availability for one or more broadcast channels. The ISP-located software communicates this availability over the narrow band two-way telephone channel to software resident in the subscriber""s computer, which displays information including the size of the desired file to be downloaded, the computed download time and associated cost for the broadband digital broadcast download path option. The software resident in the subscriber""s computer also displays similar narrow band download information, along with options for the subscriber to select the desired download method. If the slower, narrow band, two-way, point-to-point data channel is selected, a software module located at the ISP detects this selection and directs other software located at the ISP to encode and then download the desired data file over the narrow band route, which connects to Internet application software residing in the subscriber""s computer. If the faster broadcast channel option is selected, a software module located at the ISP encodes the file with a subscriber-specific identification and then (after obtaining the file from its Intemet address source) directs the desired data file to be transmitted over a high speed network link between the ISP and the broadcast channel provider, where a separate software module introduces the desired data file into the television broadcast data channel to be transmitted as part of the broadcast signal. The subscriber is billed for use of the broadcast channel. While the desired data file can be received by all broadcast channel receivers, only those with data receivers of the present invention can detect the desired data file, and only the requesting subscriber""s data receiver will identify and store the subscriber-specific encoded file. The file can be encrypted prior to transmission and decrypted upon receipt, thereby preserving privacy. The digital data demodulator of the present invention, also located at the subscribers location, demodulates the received and identified digital data, and transfers it to the subscribers computer for storage and access by the Intemet application and other applications, as necessary, thus completing the download process of the Intemet download enhancement system.